1. Field of the Invention
The present invention relates to a trocar and a trocar system, wherein a trocar tube, which is to be inserted in a patient's body and used as a guide tube for an instrument inserted in the body cavity, is made to stay in a state in which the tube has pierced and penetrated the patient's skin and body wall.
2. Description of the Related Art
In general, in the prior art, there is used a trocar apparatus wherein a trocar tube, which is to be inserted in a patient's body and used as a guide tube for an instrument inserted in the body cavity, is made to stay in a state in which the tube has pierced and penetrated the patient's skin and body wall. In the trocar apparatus, a trocar needle having a pointed pierce needle at its distal end is detachably combined with a tube having an insertion portion to be inserted in a patient.
When the trocar apparatus is to be used, the trocar needle and the tube are integrally combined in advance. In this state, the tip end of the trocar needle is made to pierce the patient's skin, and the trocar needle and tube are made to pierce the body wall and are inserted in the body cavity. Further, after the trocar has been inserted in the body cavity, the trocar needle is drawn out of the tube and thus the tube is made to stay in the body wall. Thereby, the tube can be used as a guide tube for an optical scope or an instrument for observation and treatment of a diseased part.
Jpn. Pat. Appln. KOKOKU Publication No. 5-57863, for instance, discloses an apparatus for inserting a trocar into the body cavity using ultrasonic oscillation. In the state in which a trocar needle and a tube are integrally combined, ultrasonic oscillation is transmitted to the trocar needle. The trocar needle, while being oscillated by ultrasonic waves, is made to pierce the patient's skin and body wall. In this case, by virtue of ultrasonic oscillation, the trocar can safely be made to pierce, and inserted in, the patient's body wall with a relatively weak force. Thus, the tube for guiding the instrument for treatment, etc. is inserted and made to stay in the body wall.
Jpn. Pat. Appln. KOKAI Publication No. 11-89851 shows an ultrasonic trocar system with different construction. In this system, a substantially conical, tapered adapter is provided between a trocar needle with a relatively small outside diameter and a tube. The small-diameter trocar needle is used when the trocar is inserted. Thereby, the diameter of the pierce hole made by the trocar needle in the patient's body wall is decreased and the degree of invasion on the patient is reduced. Further, the tapered adapter is inserted in the pierce hole made in the body wall. The tapered adapter increases the diameter of the pierce hole made in the body wall by the trocar needle up to the outside diameter of the tube. Accordingly, the large-diameter tube can smoothly be inserted in the pierce hole in the patient's body wall.
When the trocar needle, which is being oscillated by ultrasonic, is made to pierce the patient's skin and body wall, as disclosed in Jpn. Pat. Appln. KOKOKU Publication No. 5-57863, heat may affect the living tissue due to contact with the trocar needle that is being oscillated by ultrasonic. In order to minimize the invasion on the living tissue when the trocar needle is made to pierce the body wall, it is necessary to make the trocar needle pierce the body wall within a minimum possible time period by using the trocar needle with a relatively small outside diameter.
In the apparatus of Jpn. Pat. Appln. KOKAI Publication No. 11-89851, the diameter of a small-diameter pierce hole is increased by a conical portion of a tapered adapter up to a relatively large outside diameter of the tube. Thus, the axial length of that portion of the tapered adapter, which projects from the distal end of the tube, is relatively long. Where the distal projecting portion of the tapered adapter is long, it is possible that while the diameter of the pierce hole is being increased by the adapter, the distal end of the adapter may come in contact with, and press, an organ in the abdominal cavity. It is thus desirable that the distal projecting portion of the adapter be made as short as possible.
On the other hand, where the distal projecting portion of the adapter is short, it is possible that when the adapter is inserted in the pierce hole in the patient's body wall, it may not pierce the abdominal wall. In such a case, a time-consuming work is required. For example, the adapter used during the treatment has to be replaced with another adapter having a longer distal projecting portion. As a result, the time of work for inserting the tube in the body wall and staying it therein will increase.
In the conventional trocar apparatus, the proximal end portion of the trocar needle is engaged with the proximal end portion of the tube with a relatively weak force by means of a resilient ring such as a C-ring. Consequently, when the trocar needle is made to piece the patient's body wall, the engagement between the proximal end portion of the tube and the proximal end portion of the trocar needle may be released if the user holds the trocar apparatus at an undesirable position. As a result, the operation of the trocar apparatus becomes unstable.
Moreover, the length of the distal projecting portion of the trocar needle, which projects from the distal end of the tube, is fixed at a predetermined value. While the trocar needle is being made to pierce the patient's body wall, the amount of insertion of the distal end portion of the trocar needle is determined by the sense of the finger, the experience, etc. in accordance with conditions such as the thickness of the body wall or the location of piercing. This work is difficult and time-consuming.
The present invention has been made in consideration of the above circumstances. An object of the invention is to provide a trocar system wherein when a small-diameter pierce hole made by a trocar needle is increased up to an outside diameter of a tube, an organ in the abdominal cavity, for instance, is not pressed and the tube can easily and quickly be inserted and stayed in the body wall.
Another object of the invention is to provide a trocar system wherein when a small-diameter pierce hole made by a trocar needle is increased up to an outside diameter of a tube, an organ in the abdominal cavity, for instance, is not pressed and the tube can easily and quickly be inserted and stayed in the body wall, and also the work for inserting a distal end portion of the trocar needle can be easily and stably performed.